A track-type work vehicle such as a hydraulic excavator includes a lower traveling unit, an upper revolving unit, and a work implement coupled to this upper revolving unit. The above-described lower traveling unit has a sprocket wheel, an idler tumbler, a roller, a crawler belt apparatus, and the like.
Generally, the crawler belt apparatus is configured by coupling a plurality of crawler belt links by a pin and a bushing in an endless manner (in an oval shape) and attaching a track shoe plate to the plurality of crawler belt links. The crawler belt apparatus is wound around the idler tumbler and the sprocket wheel, and configured such that it can be driven to rotate by engaging sprocket teeth with the above-mentioned bushing to rotate the sprocket wheel.
The above-described crawler belt link has a rail surface opposite to the surface having the track shoe plate mounted thereon. On this rail surface, the rollers and the idler tumbler roll. Such a crawler belt link is, for example, disclosed in Japanese Patent Laying-Open No. 2006-89023 (see PTD 1), WO2009/101836 (see PTD 2), and the like.
Japanese Patent Laying-Open No. 2006-89023 discloses that the hardness of the rail surface of the crawler belt link is partially changed in order to reduce occurrence of level differences on the rail surface that are caused by wear due to rolling of the rollers. Furthermore, WO2009/101836 discloses that a roller is divided in the axial direction in order to reduce uneven wear of the rail surface of the crawler belt link.